title: Adipogenic and myogenic gene expression in rotator cuff muscle of the sheep after tendon tear.
abstract: Chronic rotator cuff tendon tears lead to fatty infiltration and muscle atrophy with impaired physiological functions of the affected muscles. However, the cellular and molecular mechanisms of corresponding pathophysiological processes remain unknown. The purpose of this study was to characterize the expression pattern of adipogenic (PPARgamma, C/EBPbeta) and myogenic (myostatin, myogenin, Myf-5) transcription factors in infraspinatus muscle of sheep after tenotomy, implantation of a tension device, refixation of the tendon, and rehabilitation, reflecting a model of chronic rotator cuff tears. In contrast to human patients, the presented sheep model allows a temporal evaluation of the expression of a given marker in the same individual over time. Semiquantitative RT/PCR analysis of PPARgammaã, myostatin, myogenin, Myf-5, and C/EBPbeta transcript levels was carried out with sheep muscle biopsy-derived total RNA. We found a significantly increased expression of Myf-5 and PPARgamma after tenotomy and a significant change for Myf-5 and C/EBPbeta after continuous traction and refixation. This experimental sheep model allows the molecular analysis of pathomechanisms of muscular changes after rotator cuff tear. The results point to a crucial role of the transcription factors PPARgamma, C/EBPbeta, and Myf-5 in impairment and regeneration of rotator cuff muscles after tendon tears in sheep.
authors.affiliation: Department of Orthopaedics, University of Zürich, Balgrist, Zürich, Switzerland.
authors.forename: Eric
authors.initials: E
authors.lastname: Frey
authors.forename: Felix
authors.initials: F
authors.lastname: Regenfelder
authors.forename: Patrick
authors.initials: P
authors.lastname: Sussmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Zumstein
authors.forename: Christian
authors.initials: C
authors.lastname: Gerber
authors.forename: Walter
authors.initials: W
authors.lastname: Born
authors.forename: Bruno
authors.initials: B
authors.lastname: Fuchs
mesh_terms: D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics* / Q000502:physiology; D004195:Disease Models, Animal; D015870:Gene Expression; D051787:Myogenic Regulatory Factor 5 / Q000235:genetics* / Q000502:physiology; D018008:Myogenin / Q000235:genetics*; D055435:Myostatin / Q000235:genetics*; D047495:PPAR gamma / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D012038:Regeneration; D017006:Rotator Cuff / Q000378:metabolism*; D000070636:Rotator Cuff Injuries; D012756:Sheep; D013708:Tendon Injuries / Q000378:metabolism
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D051787:Myogenic Regulatory Factor 5; D018008:Myogenin; D055435:Myostatin; D047495:PPAR gamma; D012333:RNA, Messenger